Unprecedently low thermal conductivity of unique tellurium nanoribbons

What is it about?

Tellurene, probably one of the most promising two-dimensional (2D) system in the thermoelectric materials, displays ultra-low thermal conductivity. However, a linear thickness-dependent thermal conductivity of unique tellurium nanoribbons in this study reveals that unprecedently low thermal conductivity can be achieved via well-defined nanostructures of low-dimensional tellurium instead of pursuing dimension-reduced 2D tellurene. For thinnest tellurium nanoribbon with thickness of 144 nm, the thermal conductivity is only ~1.88 ± 0.22 W·m−1·K−1 at room temperature. It’s a dramatic decrease (45%), compared with the well-annealed high-purity bulk tellurium. To be more specific, an expected thermal conductivity of tellurium nanoribbons is even lower than that of 2D tellurene, as a result of strong phonon-surface scattering. We have faith in low-dimensional tellurium in which the thermoelectric performance could realize further breakthrough.

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Photo by Mika Baumeister on Unsplash

Photo by Mika Baumeister on Unsplash

Why is it important?

To conclude, the monocrystal Te nanoribbons were synthesized by solution chemical method, and we measured the thermal conductivity of Te nanoribbons with various thickness. The thickness-dependent thermal conductivity with an almost linear relationship is discovered, caused by severe phonon-surface scattering. In thinnest sample with ~148 nm in thickness, thermal conductivity is as low as ~ 1.88 ± 0.22 W·m−1·K−1 at room temperature, which is nearly half of that of the well-annealed high-purity bulk Te. These results provide new experimental evidence for research of unconventional thermal conduction in low-dimensional materials and it is promising to achieve outstanding thermoelectric property in low-dimensional Te.

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